Alliant Energy Corporation
US ˙ NasdaqGS ˙ US0188021085

SecurityLNT / Alliant Energy Corporation
InstitutionSei Investments Co
Latest Disclosed Ownership245,652 shares
Latest Disclosed Value $ 15,970,448
Sei Investments Co reports 26.01% increase in ownership of LNT / Alliant Energy Corporation

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 245,652 shares of Alliant Energy Corporation (US:LNT) valued at $15,969,837 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 194,948 shares of Alliant Energy Corporation. This represents a change in shares of 26.01% during the quarter. The current value of the position is $17,389,705 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-02-13 2025-12-31 13F ALLIANT ENERGY COM 018802108 245,652 50,704 26.01 15,970 21.53 0.0158
2025-11-13 2025-09-30 13F ALLIANT ENERGY COM 018802108 194,948 103,303 112.72 13,141 137.16 0.0141
2025-08-14 2025-06-30 13F ALLIANT ENERGY COM 018802108 91,645 -85,034 -48.13 5,542 -51.26 0.0064
2025-05-14 2025-03-31 13F/A-1 ALLIANT ENERGY COM 018802108 176,679 -99,002 -35.91 11,369 -30.26 0.0146
2025-05-13 2025-03-31 13F ALLIANT ENERGY COM 018802108 277,018 1,337 16,400 0.0178
2025-02-11 2024-12-31 13F ALLIANT ENERGY COM 018802108 275,681 -99,524 -26.53 16,304 -28.40 0.0209
2024-11-12 2024-09-30 13F ALLIANT ENERGY COM 018802108 375,205 153,125 68.95 22,771 101.46 0.0296
2024-08-13 2024-06-30 13F ALLIANT ENERGY COM 018802108 222,080 130,972 143.75 11,304 146.20 0.0160
2024-05-07 2024-03-31 13F ALLIANT ENERGY COM 018802108 91,108 -122,971 -57.44 4,592 -58.20 0.0067
2024-02-14 2023-12-31 13F ALLIANT ENERGY COM 018802108 214,079 32,785 18.08 10,982 25.04 0.0176
2023-11-14 2023-09-30 13F ALLIANT ENERGY COM 018802108 181,294 -1,949 -1.06 8,784 -8.66 0.0158
2023-08-11 2023-06-30 13F ALLIANT ENERGY COM 018802108 183,243 -16,214 -8.13 9,617 -9.71 0.0168
2023-05-12 2023-03-31 13F ALLIANT ENERGY COM 018802108 199,457 -6,755 -3.28 10,651 -6.46 0.0198
2023-02-10 2022-12-31 13F ALLIANT ENERGY COM 018802108 206,212 -66,813 -24.47 11,385 -21.31 0.0253
2022-11-14 2022-09-30 13F ALLIANT ENERGY COM 018802108 273,025 136,735 100.33 14,468 81.12 0.0323
2022-08-15 2022-06-30 13F ALLIANT ENERGY COM 018802108 136,290 116,638 593.52 7,988 550.49 0.0173
2022-05-13 2022-03-31 13F ALLIANT ENERGY COM 018802108 19,652 -68,586 -77.73 1,228 -77.36 0.0025
2022-02-14 2021-12-31 13F ALLIANT ENERGY COM 018802108 88,238 1,574 1.82 5,425 11.81 0.0102
2021-11-12 2021-09-30 13F ALLIANT ENERGY COM 018802108 86,664 -33,572 -27.92 4,852 -27.63 0.0102
2021-08-06 2021-06-30 13F ALLIANT ENERGY COM 018802108 120,236 -78,019 -39.35 6,704 -37.56 0.0149
2021-05-12 2021-03-31 13F ALLIANT ENERGY COM 018802108 198,255 -37,585 -15.94 10,737 -11.65 0.0271
2021-02-08 2020-12-31 13F ALLIANT ENERGY COM 018802108 235,840 -25,326 -9.70 12,153 -9.90 0.0314
2020-12-04 2020-09-30 13F/A-1 ALLIANT ENERGY COM 018802108 261,166 45,763 21.25 13,489 30.90 0.0391
2020-11-06 2020-09-30 13F ALLIANT ENERGY COM 018802108 262,501 47,098 13,558 32,644.6495
2020-08-17 2020-06-30 13F/A-1 ALLIANT ENERGY COM 018802108 215,403 -23,647 -9.89 10,305 -10.73 0.0320
2020-08-11 2020-06-30 13F ALLIANT ENERGY COM 018802108 217,074 -21,976 11,869 32,195.2943
2020-05-14 2020-03-31 13F ALLIANT ENERGY COM 018802108 239,050 23,189 10.74 11,544 -2.27 0.0424
2020-02-06 2019-12-31 13F ALLIANT ENERGY COM 018802108 215,861 -22,513 -9.44 11,812 -8.12 0.0352
2019-11-12 2019-09-30 13F ALLIANT ENERGY COM 018802108 238,374 -13,786 -5.47 12,856 3.88 0.0329
2019-08-14 2019-06-30 13F ALLIANT ENERGY COM 018802108 252,160 -41,155 -14.03 12,376 -10.47 0.0404
2019-05-15 2019-03-31 13F ALLIANT ENERGY COM 018802108 293,315 81,826 38.69 13,824 53.55 0.0464
2019-02-13 2018-12-31 13F ALLIANT ENERGY COM 018802108 211,489 -36,012 -14.55 9,003 -14.55 0.0321
2018-11-08 2018-09-30 13F ALLIANT ENERGY COM 018802108 247,501 44,867 22.14 10,536 22.87 0.0382
2018-08-03 2018-06-30 13F ALLIANT ENERGY COM 018802108 202,634 189,850 1,485.06 8,575 1,542.72 0.0291
2018-05-11 2018-03-31 13F ALLIANT ENERGY COM 018802108 12,784 -165,151 -92.82 522 -93.91 0.0020
2018-02-08 2017-12-31 13F ALLIANT ENERGY COM 018802108 177,935 -29,751 -14.32 8,577 -0.63 0.0298
2017-11-06 2017-09-30 13F ALLIANT ENERGY COM 018802108 207,686 -1,449 -0.69 8,631 2.74 0.0307
2017-07-31 2017-06-30 13F ALLIANT ENERGY COM 018802108 209,135 52,886 33.85 8,401 35.74 0.0335
2017-05-05 2017-03-31 13F ALLIANT ENERGY COM 018802108 156,249 21,880 16.28 6,189 21.23 0.0271
2017-02-02 2016-12-31 13F ALLIANT ENERGY COM 018802108 134,369 21,498 19.05 5,105 18.06 0.0247
2016-11-04 2016-09-30 13F ALLIANT ENERGY COM 018802108 112,871 17,012 17.75 4,324 13.61 0.0220
2016-08-11 2016-06-30 13F ALLIANT ENERGY COM 018802108 95,859 42,132 78.42 3,806 -4.64 0.0228
2016-05-10 2016-03-31 13F/A-1 ALLIANT ENERGY COM 018802108 53,727 4,094 8.25 3,991 28.74 0.0248
2016-02-03 2015-12-31 13F ALLIANT ENERGY COM 018802108 49,633 27,734 126.65 3,100 141.81 0.0189
2015-11-02 2015-09-30 13F/A-1 ALLIANT ENERGY COM 018802108 21,899 -1,824 -7.69 1,282 -6.36 0.0118
2015-10-30 2015-09-30 13F ALLIANT ENERGY COM 018802108 21,899 1,282
2015-08-07 2015-06-30 13F/A-1 ALLIANT ENERGY COM 018802108 23,723 -3,721 -13.56 1,369 -20.68 0.0124
2015-08-04 2015-06-30 13F ALLIANT ENERGY COM 018802108 23,723 -3,721 1,369 0.0124
2015-05-14 2015-03-31 13F/A-1 ALLIANT ENERGY COM 018802108 27,444 9,377 51.90 1,726 43.95 0.0150
2015-05-01 2015-03-31 13F ALLIANT ENERGY COM 018802108 27,444 1,726
2015-02-10 2014-12-31 13F ALLIANT ENERGY COM 018802108 18,067 18,067 1,199 0.0106
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.